In a mixing bowl, whisk together flour, eggs, milk, melted butter, and a pinch of salt until smooth.
Heat a non-stick pan over medium heat. Pour ¼ cup of batter into the pan, tilting to coat the surface evenly. Cook until the edges start to lift, then flip and cook the other side. Repeat with remaining batter.
In another bowl, combine crab meat, mayonnaise, lemon juice, chives, salt, and black pepper. Mix well.
Place a spoonful of crab filling in the center of each crepe and fold over. Serve warm.